Perinatal outcomes of selective termination in dichorionic twin pregnancies: a retrospective study from a single center.

Objective: Selective termination (ST) is an appropriate procedure for managing discordant fetal anomalies in dichorionic diamniotic (DCDA) twin pregnancies. The aim of this study was to investigate the perinatal outcomes of ST at different gestational ages in DCDA twin pregnancies.

Methods: This retrospective study was conducted on DCDA twin pregnancies with STs at West China Second University Hospital between January 2012 and December 2022. According to the gestational age at which ST was performed, the patients were assigned to four groups: Group 1 (13 to 17 + 6 weeks), Group 2 (18 to 23 + 6 weeks), Group 3 (24 to 27 + 6 weeks), and Group 4 (≥ 28 weeks).

Results: We identified 230 patients for this study. The overall rates of miscarriage, preterm delivery at < 32 weeks, and term delivery were 1.3%, 10.5%, and 50%, respectively, while the rates of live birth and neonatal survival were 98.7% and 98.2%, respectively. The rate of term birth was highest (70.6%) and the birth weight was heaviest (2931 ± 535 g) in Group 1 (p = 0.000). In the presence of a fetus subjected to feticide, the mean delivery age was earlier than that in the non-presenting group (p = 0.017); accordingly, the mean birth weight in the feticide group was lower (2366 ± 628 g) than that in the non-presenting group (2590 ± 634 g) (p = 0.011). When we examined the relative relationship between reduction weeks and delivery weeks of twins by correlation analysis, we observed that with regard to maternal prognosis, two pregnancies involved preterm premature rupture of membranes (PPROM) at 7 days and 3 days after the procedure. Intrauterine infection occurred in two patients in Group 4, but there were no maternal deaths or maternal coagulatory abnormalities.

Conclusions: Optimal perinatal outcomes were obtained by ST of DCDA pregnancies before 18 weeks, regardless of whether or not the reduced fetus was the presenting twin. However, if legally possible, late (i.e., after 28 weeks) procedures can be a safe alternative for patients diagnosed after the 18th week of gestation. Overall, we herein noted a negative correlation between the procedure week and the delivery week in this study. Moreover, ST of the non-presenting twin was associated with a heavier birth weight and later gestational age at delivery.